Method and system for providing explosion proof video and communication relay module

ABSTRACT

Embodiments of methods, devices and systems are presented for communicating information in an explosive environment. An explosion proof video and data communication module includes features that prevent the generation of a spark or other ignition sources that could ignite explosive dust, gas or vapors in the air. The explosion proof video and communications relay modules may operate independently or as a group to provide real-time information, situation awareness, functionally and responsiveness for personnel that are in explosive environments.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/627,666 titled “Method and System for Providing Explosion Proof Videoand Communication Relay Module” filed on Sep. 26, 2012, which claims thebenefit of priority to each of U.S. Provisional Application No.61/626,440, entitled “Method and System for Providing Explosion ProofVideo and Communication Relay Module” filed Sep. 27, 2011, and U.S.Provisional Application No. 61/626,441, entitled “Method and System forProviding Explosion Proof Emergency Communication Relay Module” filedSep. 27, 2011, the entire contents of all of which are herebyincorporated by reference.

BACKGROUND

Each day workers put themselves at risk by working in dangerous orpotentially dangerous environments involving explosive vapors or gasses.For example, in addition to the risk of cave-ins, sub-surface minersface the risk toxic fumes and explosive gases on a daily basis. Asanother example, firemen and other first responders frequently have toventure into buildings, subways and sewers filled with explosive gassesin order rescue victims and save property.

Chief among the dangers facing such workers is the possibility of anexplosion due to detonation of explosive vapors, gasses and dustsuspended in the air in a confined space. One of the top causes of mineexplosions is the detonation of explosive gases, such as methane, whichcan enter the mine through the Earth that is being mined. If properventilation procedures are not taken, methane gas (or other explosivegases) may collect in the mine Any ignition source may explosivelyignite the gas and lead to catastrophic results.

Fire and rescue personnel face similar dangers when hurricane, tornadoor terrorist attacks leave buildings in ruble with natural gas linesleaking. As another example, fire and rescue personnel responding torefinery incidents, and automobile and aircraft accidents can faceexplosive vapor situations resulting from gasoline and diesel fumes.While gas and vapor levels in one part of a building appear safe, gasand fumes can accumulate in pockets, pits or enclosed rooms to reachpotentially explosive concentrations.

In addition to explosive gases, combustible dust can give rise to anexplosive environment. Such dust explosion risks can arise in a varietyof situations such as factory mishaps, grain milling and storagefacilities.

In addition to fire and rescue personnel, many work environments requirecommunications in the presence of explosive gasses and vapors. TheOccupational Safety and Health Administration (OSHA) has classified anumber of hazardous work environments where special precaution must betaken to provide workers with safe working conditions. The most extremework environment is classified as Class I, Division 1. A Class I,Division I work environment is a location in which: (a) hazardousconcentrations of flammable gases or vapors may exist under normaloperating conditions; (b) hazardous concentrations of such gases orvapors may exist frequently because of repair or maintenance operationsor because of leakage; or (c) breakdown or faulty operation of equipmentor processes might release hazardous concentrations of flammable gasesor vapors, and might also cause simultaneous failure of electricequipment.

Examples of work locations where Class I, Division I classifications aretypically assigned include locations where volatile flammable liquids orliquefied flammable gases are transferred from one container to another,interiors of spray booths and areas in the vicinity of spraying andpainting operations where volatile flammable solvents are used,locations containing open tanks or vats of volatile flammable liquids,drying rooms or compartments for the evaporation of flammable solvents,locations containing fat and oil extraction equipment using volatileflammable solvents, portions of cleaning and dyeing plants whereflammable liquids are used, gas generator rooms and other portions ofgas manufacturing plants where flammable gas may escape, inadequatelyventilated pump rooms for flammable gas or for volatile flammableliquids, the interiors of refrigerators and freezers in which volatileflammable materials are stored in open, lightly stoppered, or easilyruptured containers; and all other locations where ignitableconcentrations of flammable vapors or gases are likely to occur in thecourse of normal operations.

For personnel who work in such environments on a daily basis, acommunication system to improve situation awareness is needed so thosepersonnel can safely operate in explosive environments. Similarly,emergency services personnel who may have to enter explosiveenvironments to respond to emergency situations need an explosion-proofcommunication system to improve the situation awareness both in terms ofvoice communication as well as visual and other telemetry methods.

Additionally not only is situation awareness needed by the personnelentering into the explosive environment their command structure needs tohave eyes and ears on the ground to have real time information so thatthe situation can be properly sized up and the requisite resources canbe applied, reassigned or personnel in the explosive environments can beinformed if and when it is best to exit the location.

SUMMARY

The various embodiments include an explosion-proof communication device,which may include, a non-conductive housing, a first antenna, a secondantenna, a radio receiver, a radio transmitter, a battery coupled to afault tolerant circuit element, a processor coupled to the firstantenna, second antenna, radio receiver, radio transmitter, and battery.The processor may be configured with processor executable softwareinstructions to perform operations including, receiving radio frequencysignals from the first antenna at a first frequency, and retransmittingthe received frequency signals from the second antenna at a secondfrequency. In an embodiment, the first frequency may be different fromthe second frequency. In an embodiment, the processor, first antenna,second antenna, radio receiver, radio transmitter, battery, and faulttolerant circuit element are hermetically sealed inside thenon-conductive housing. In an embodiment, the battery may be arechargeable battery, and the explosion-proof communication devicefurther including, a rectifier coupled to the rechargeable battery, andan induction coil coupled to the rectifier. In an embodiment, theinduction coil and rectifier are configured to generate a voltageoperable to charge the rechargeable battery when an alternating magneticfield may be applied to the induction coil.

In a further embodiment, the explosion-proof communication deviceincludes, a transistor coupled between the rectifier and therechargeable battery with a control lead coupled to the processor, andthe processor may be configured with processor-executable softwareinstructions to perform operation further including, regulating thecharging of the rechargeable battery when the voltage is generated bythe induction coil and rectifier. In a further embodiment, the radioreceiver and radio transmitter may include, a signal generatorconfigured to generate a radio frequency signal having a thirdfrequency.

In a further embodiment, the processor may be configured withprocessor-executable software instructions to perform operation furtherincluding, adjusting the frequency in of the radio frequency signalgenerated by the signal generator. In a further embodiment, theprocessor may be configured with processor-executable softwareinstructions to perform operations further including, controlling anoutput power of the radio receiver and radio transmitter to maintain theoutput power at a minimum level consistent with a minimum quality of theservice metric and below a maximum output power level. In a furtherembodiment, the processor may be configured with processor-executablesoftware instructions to perform operations further including, groupingthe relay device with a wireless transceiver in proximity to the relaydevice to form a communication group, in which receiving radio frequencysignals from the first antenna at a first frequency may includereceiving receive radio frequency signals from the wireless transceiverin the communication group.

In a further embodiment, the explosion-proof communication deviceincludes a fastener attached to the non-conductive housing andconfigured to secure the explosion-proof communication relay device to ahelmet. In a further embodiment, the fastener may include a strap. In afurther embodiment, fastener may include a fabric hook-and-loopfastening element. In a further embodiment, the explosion-proofcommunication device may include a selector switch coupled to thenon-conductive housing and arranged so that it may be actuated by ahuman user wearing gloves to cause the processor to perform one or moreoperations. In a further embodiment, the explosion-proof communicationdevice may include a camera, and a lens cover arranged to seal andisolate the camera from an exterior atmosphere. In a further embodiment,the explosion-proof communication device may include an illuminationsource mounted behind a camera lens of the camera and arranged so as tonot impede the illumination capability of the illumination source.

In an embodiment, the processor may be configured withprocessor-executable software instructions to perform operations furtherincluding, receiving instructions from a second explosion-proofcommunication relay device, and adjusting a resolution of videoinformation collected by the camera based on the received instructions.In a further embodiment, the explosion-proof communication device mayinclude a sensor hermetically sealed inside the non-conductive housingand configured to monitor environmental conditions outside thenon-conductive housing. In a further embodiment, the explosion-proofcommunication device may include an audio circuit hermetically sealedinside the non-conductive housing and configured to a microphone and aspeaker outside of the non-conductive housing from within thehermetically sealed non-conductive housing.

Further embodiments include a communication system for use in anexplosive environment including a first and second explosion-proofcommunication relay device, each of which may include, a non-conductivehousing, a first antenna, a second antenna, a radio receiver, a radiotransmitter, a battery coupled to a fault tolerant circuit element, aprocessor coupled to the first antenna, second antenna, radio receiver,radio transmitter, and battery, in which the processor may be configuredwith processor executable software instructions to perform operationsincluding, receiving radio frequency signals from the first antenna at afirst frequency, and retransmitting the received frequency signals fromthe second antenna at a second frequency. In an embodiment, the firstfrequency may be different from the second frequency. In an embodiment,the processor, first antenna, second antenna, radio receiver, radiotransmitter, battery, and fault tolerant circuit element arehermetically sealed inside the non-conductive housing. In an embodiment,the processor of the first explosion-proof communication relay devicemay be further configured with processor executable softwareinstructions to perform operations further including, establishing acommunication link with the second explosion-proof communication relaydevice.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and constitutepart of this specification, illustrate exemplary embodiments of theinvention, and, together with the general description given above andthe detailed description given below, serve to explain features of theinvention.

FIG. 1 is a system block diagram illustrating information flows,communication links, and components in an example communication systemin which an embodiment explosion-proof relay module may be deployed.

FIG. 2 is an illustration of an embodiment explosion-proof relay modulemounted on helmet suitable for use emergency personnel in explosiveenvironments.

FIG. 3 is a block diagram illustrating various components that may beincluded in an embodiment explosion-proof relay module.

FIGS. 4-5 are component block diagrams illustrating various logical andfunctional components of an embodiment explosion-proof relay module.

FIGS. 6-8 are front, side, and rear view illustrations of embodimentexplosion-proof relay modules.

FIG. 9 is an illustration of another embodiment explosion-proof relaymodule suitable for use by personnel that may or may not be required toenter an explosive environment.

FIG. 10 is component block diagrams illustrating various additionallogical and functional components that may be included in an embodimentexplosion-proof relay module.

FIGS. 11-13 are front and rear view illustrations of another embodimentexplosion-proof relay module.

FIG. 14 is a process flow diagram illustrating an embodiment method ofgrouping multiple explosion-proof relay modules to perform group relayoperations.

FIG. 15 is a process flow diagram illustrating an embodimentexplosion-proof relay module method of communicating telemetryinformation by performing group relay operations.

FIG. 16 is a process flow diagram illustrating another embodimentexplosion-proof relay module method of communicating telemetryinformation.

FIG. 17 is a block diagram illustrating an example charging receptacleand various components that may be included an embodimentexplosion-proof relay module to support the recharging of a battery ofthe explosion-proof relay module.

FIG. 18 is an illustration of a charging base suitable for use with thevarious embodiments.

FIG. 19 is an illustration of a top portion of a charging base suitablefor use with the various embodiments.

FIG. 20 is an illustration of a top portion of another charging basesuitable for use with the various embodiments.

FIG. 21 is an illustration of a top portion of yet another charging basesuitable for use with the various embodiments.

FIG. 22 is a block diagram illustrating communication links andcomponents that may included in an embodiment explosion-proof relaymodule to support audio communications.

FIG. 23 is a component block diagram illustrating various componentscommonly included in a mobile transceiver device that are suitable foruse in an embodiment explosion-proof relay module.

FIG. 24 is a component block diagram of a server suitable for use withan embodiment.

DETAILED DESCRIPTION

The various embodiments will be described in detail with reference tothe accompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.References made to particular examples and implementations are forillustrative purposes, and are not intended to limit the scope of theinvention or the claims.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration.” Any implementation described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other implementations.

The terms “mobile device,” “cellular telephone,” and “cell phone” areused interchangeably herein to refer to any one or all of cellulartelephones, smartphones, personal data assistants (PDA's), laptopcomputers, tablet computers, ultrabooks, palm-top computers, wirelesselectronic mail receivers, multimedia Internet enabled cellulartelephones, wireless gaming controllers, and similar personal electronicdevices which include a programmable processor, a memory and circuitryfor sending and/or receiving wireless communication signals.

The terms “wireless network,” “network,” “cellular system,” “celltower,” and “radio access point” are used generically herein to refer toany one of various wireless mobile systems, technologies, and/orcomponents. In an embodiment, wireless network may be a radio accesspoint (e.g., a cell tower), which provides a radio link to the mobiledevice so that the mobile device can communicate with core networkcomponents.

A number of different methods, technologies, solutions, and/ortechniques (herein collectively “solutions”) are currently available fordetermining the location of mobile device, any or all of which may beimplemented by, included in, and/or used by the various embodiments.Such solutions include, e.g., global positioning system (GPS) basedsolutions, assisted GPS (A-GPS) solutions, and cell-based positioningsolutions such as cell of origin (COO), time of arrival (TOA), observedtime difference of arrival (OTDOA), advanced forward link trilateration(AFLT), and angle of arrival (AOA). In various embodiments, suchsolutions may implemented in conjunction with one or more wirelesscommunication technologies and/or networks, including wireless wide areanetworks (WWANs), wireless local area networks (WLANs), wirelesspersonal area networks (WPANs), and other similar networks ortechnologies. By way of example, a WWAN may be a Code Division MultipleAccess (CDMA) network, a Frequency Division Multiple Access (FDMA)network, an OFDMA network, a 3GPP LTE network, a WiMAX (IEEE 802.16)network, and so on. The WPAN may be a Bluetooth network, an IEEE 802.15xnetwork, and so on. A WLAN may be an IEEE 802.11x network, and so on. ACDMA network may implement one or more radio access technologies (RATs)such as CDMA2000, Wideband-CDMA (W-CDMA), and so on.

As used in this application, the terms “component,” “module,” “engine,”“manager” are intended to include a computer-related entity, such as,but not limited to, hardware, firmware, a combination of hardware andsoftware, software, or software in execution, which are configured toperform particular operations or functions. For example, a component maybe, but is not limited to, a process running on a processor, aprocessor, an object, an executable, a thread of execution, a program, acomputer, a server, network hardware, etc. By way of illustration, bothan application running on a computing device and the computing devicemay be referred to as a component. One or more components may residewithin a process and/or thread of execution and a component may belocalized on one processor or core and/or distributed between two ormore processors or cores. In addition, these components may execute fromvarious non-transitory computer readable media having variousinstructions and/or data structures stored thereon.

A number of different cellular and mobile communication services andstandards are available or contemplated in the future, all of which mayimplement and benefit from the various embodiments. Such services andstandards include, e.g., third generation partnership project (3GPP),long term evolution (LTE) systems, third generation wireless mobilecommunication technology (3G), fourth generation wireless mobilecommunication technology (4G), global system for mobile communications(GSM), universal mobile telecommunications system (UMTS), 3GSM, generalpacket radio service (GPRS), code division multiple access (CDMA)systems (e.g., cdmaOne, CDMA2000TM), enhanced data rates for GSMevolution (EDGE), advanced mobile phone system (AMPS), digital AMPS(IS-136/TDMA), evolution-data optimized (EVDO), digital enhancedcordless telecommunications (DECT), Worldwide Interoperability forMicrowave Access (WiMAX), wireless local area network (WLAN), publicswitched telephone network (PSTN), Wi-Fi Protected Access I & II (WPA,WPA2), Bluetooth®, integrated digital enhanced network (iden), and landmobile radio (LMR). Each of these technologies involves, for example,the transmission and reception of voice, data, signaling and/or contentmessages. It should be understood that any references to terminologyand/or technical details related to an individual telecommunicationstandard or technology are for illustrative purposes only, and are notintended to limit the scope of the claims to a particular communicationsystem or technology unless specifically recited in the claim language.

The manufacture, processing, mining, transport, and/or storage ofcertain materials may create or release gases, vapors, and/orcombustible dust into the environment, which when combined with oxygenin the air, may create an explosive environment. To minimize the risk ofan explosion, equipment used by workers who venture into such hazardousenvironments typically cannot include any components that may causesparks or otherwise become an ignition source.

Conventional mobile electronic devices, such as mobile phones andcameras, typically include exposed metal components and electroniccircuitry that may cause sparks or otherwise ignite a highly explosiveenvironment. Therefore, conventional mobile electronic devices are notsuitable for use in explosive environments, and must be removed by firstresponders (e.g., police, fire, and emergency personnel) entering ahazardous area.

The various embodiments provide scalable, wireless, multi-channel,and/or two-way communication devices and systems suitable for use inexplosive environments. Various embodiments include explosion-resistantor explosion-proof communications module/device having hermeticallysealed components and/or fault-tolerant electronic circuitry that isresistant to heat and sparks.

Various embodiments include an explosion-resistant communication systemthat includes an explosion-proof video and communication relay moduleand one or more explosion-proof mobile devices, such as hermeticallysealed cellular telephones, radio communication modules, video cameras,led lighting, sensors, and other devices suitable for use in explosiveenvironments.

The explosion-proof communication relay modules may be configured toprovide enhanced situation awareness capabilities in an explosiveenvironment, which is of particular importance to first responders andemergency personnel deployed in disaster sites. An explosion-proof videoand communication relay module may also include fault-tolerantelectronics, which may be battery powered and enclosed within anon-metallic sealed housing to reduce or remove threats from sparksand/or heat. In an embodiment, the explosion-proof video andcommunication relay module may include an inductive charging elementbuilt into its housing to enable charging of the battery without anyexposed metal contacts that could serve as a source for a spark. In anembodiment, the explosion-proof video and communication relay module mayinclude control buttons sized to enable operation by personnel wearinggloves and protective clothing.

FIG. 1 illustrates example components in an explosion-resistantcommunication system 100 according to an embodiment. In the exampleillustrated in FIG. 1, the explosion-resistant communication system 100includes a sensor module 122, multiple explosion-proof video andcommunication relay modules 102, and a local or small cell site 104. Thelocal/small cell site 104 may be installed at the incident scene or on amobile platform, such as the illustrated fire engine/truck 106. Therelay modules 102 may be installed on equipment worn or carried by firstresponders, emergency services personnel, and/or workers at the incidentscene. The relay modules 102 may be explosion-proof components in whichall of the circuitry, electronics, wires, contacts, and metal elementsare encapsulated in a hermetic or airtight sealed case/housing formedfrom non-conductive materials.

The sensor module 122 may include one or more explosion-proof devices(not illustrated), which may be linked into the communicationarchitecture of one or more of the relay modules 102. The sensor module122 may be embedded in a relay module 102, external to the relay module102, in communication with a relay module 102, or any combinationthereof.

The local/small cell site 104 may be configured to communicate with thesensor module 122 and various mobile devices, such as the illustratedcellular phone 112, handheld computer-like tablet of an incidentcommander 114, and laptop 116. The local/small cell site 104 may also beconfigured to communicate with a variety of other mobile devices andcommunication centers via the radio access node 120 coupled to acommercial or private cellular communications network. In the exampleillustrated in FIG. 1, the local/small cell site 104 communicates withsafety personnel 130, emergency medical services 132, smartphones 108,hospitals 134, dispatch centers 136, and radio access devices 110, allvia the radio access node 120.

The radio access nodes 120 may operate to connect voice and data callsbetween mobile devices (e.g., mobile phones), data centers, thelocal/small cell site 104, the relay modules 102, and/or other networkdestinations, such as via telephone land lines (e.g., a POTS network,not shown) and the Internet. In various embodiments, the radio accessnodes 120 may include any wireless base station or radio access point(e.g., LTE, CDMA2000/EVDO, WCDMA/HSPA, IS-136, GSM, WiMax, WiFi, AMPS,DECT, TD-SCDMA, or TD-CDMA), a switch, Land Mobile Radio (LMR)interoperability equipment, a satellite Fixed Service Satellite (FSS)for remote interconnection to the Internet and PSTN, a networkoperations center, and/or other components for sending and receivingcommunication signals to and from various network components.

When implemented in a 3GPP-LTE network, radio access nodes 120 mayinclude an Evolved Serving Mobile Location Center (E-SMLC) componentconfigured to send and receive location information (e.g., latitude,longitude, altitude, velocity, etc.) to and from the mobile devices andrelay modules 102, which may be achieved both on-net and off-net. Thelocation information may be delivered in standard formats, such as thosefor cell-based or geographical co-ordinates, together with the estimatederrors (uncertainty) of the location, position, altitude, and velocityof a mobile device and, if available, the positioning method (or thelist of the methods) used to obtain the position estimate. In anembodiment, the E-SMLC may be configured to provide location servicesvia a lightweight presentation protocol LPP that supports the provisionof application services on top of TCP/IP networks. In an embodiment, theE-SMLC may also send and/or receive (e.g., via LPP) almanac and/orassistance data to and from core components, such as an eNodeB and amobility management entity (MME).

The relay modules 102 may include communications circuitry for sendingand receiving voice, data, content, images, video, broadbandinformation, and other communications/information to and from each other102, the local/small cell site 104, mobile devices 108, 110, 140, andcellular communications networks (both commercial and private). Therelay modules 102 may communicate with the cellular networks via theradio access node 120. The mobile devices 108, 110, 140 may includesmartphones 108, radio communication devices 110 (e.g., VHF, UHF, LMR,and/or P25 HT communications devices), and other intrinsically safecommunication devices 140 configured to present voice, data, content,images, video and broadband information to a person wearing or holdingthe respective device 108, 110, 140.

The relay modules 102 may be configured so that cellular telephonecommunications in the 700 MHz Public Safety band (or any other frequencyband, such as 450 MHz, 700 MHz, 850 MHz bands, the 1710-1755 MHz and2110-2155 MHz AWS bands, etc.) are communicated between the radio accessnodes 120, cellular telephones 112, and the relay modules 102 infrequency-division duplex and/or time-division duplex formats. In otherembodiments, relay modules 102 may be configured to communicate any orall cellular telephone frequencies currently available or which may beused in the future.

In various embodiments, the explosion-resistant communication system 100may be implemented on half-duplex and/or full-duplex communicationsystems. For cellular telephone communications, which may be full duplexsystems that use different frequencies for transmitting and receivinginformation, different frequencies may be used for conveyingcommunication signals between the relay modules 102 and mobile devices,such as cellular phones 112. For example, a first relay module 102 maybe configured to receive transmissions from a radio access node 120 in afirst modulation format (e.g., time, frequency, etc.) or technology, andrelay the received transmissions to a second relay module 102 in asecond modulation format or technology. The second relay module 102 mayrelay the received transmissions to the cellular phone 112 in a formatsupported by that cellular phone 112. In this manner, any of a number ofcommercially available cellular phones 112 may be deploy in, orsupported by, the explosion-resistant communication system 100, withoutrequiring any modifications to the transceivers or other components ofthe cellular phone 112.

In various embodiments, the relay modules 102 may be configured toselect a frequency range for relaying communication signals betweenvarious components, such as between a radio access node 120 and a mobiledevice 108.

In an embodiment, the relay modules 102 may be configured to select arelay frequency that reduces likelihood of the electromagnetic radiationinducing currents in surrounding metals. This configuration isparticularly useful for emergency services applications, where the relaymodules 102 may be deployed in confined areas and/or areas with limitedradio frequency transmission capabilities (e.g., underground in subways,sewers, mines, tunnels or explosion craters).

In an embodiment, the relay modules 102 may be configured to select arelay frequency based upon the transmission characteristics of thecommunication signals.

In various embodiments, the relay frequency may be selected with orwithout concern for interference with other frequencies, such asfrequencies allocated to other commercial communication systems.

In an embodiment, the relay modules 102 may be configured to select arelay frequency based on the conditions of local communications systems.For example, in an embodiment, a relay module 102 may be configured todetect the presence of other communication systems and/or communicationsignals within the vicinity of the incident scene, and select a relayfrequency that is not likely to interfere with the detectedcommunication systems/signals. Alternatively, or in addition todetecting the presence of other communications systems, the relaymodules 102 may be configured to select a relay frequency so as toreduce the likelihood of interference with other communications known toexist in the vicinity of the incident scene. Such configurations may beparticularly useful when the explosion-proof video and relay modules 102are deployed in certain hazardous environment (e.g., mining, chemicaland/or petroleum industrial facilities) and/or used for non-emergencyapplications.

In an embodiment, the relay modules 102 may be configured to select arelay frequency based on licensing agreements and/or frequency-userequirements, such as a license agreement with the FederalCommunications Commission (FCC) that constrains or restricts the use ofthe available frequency bands. This configuration may be particularlyuseful in above-ground applications, where communication signals relayedby the relay modules 102 are more likely to interfere with communicationsignals in a frequency range controlled by the FCC.

The relay modules 102 may be configured to select a relay frequencybased on any or all of the factors discussed above.

The relay modules 102 may operate in a point-to-point communication andrelay scheme. The relay modules 102 may also operate in a mesh, loop,and/or a self-healing environment. In an embodiment, relay modules 102and/or mobile devices 108, 110, 112, 114, 116, and 140 may be configuredto automatically establish a mesh, loop, and/or a self-healing networkin response to detecting that direct point-to-point communications arenot available. In an embodiment, the relay modules 102 may be organizedin a self-healing ring, which may include each relay module 102 having abidirectional link to two or more of the other relay modules 102.

In an embodiment, the relay modules 102 may include a cellularcommunications module. In an embodiment, the mobile devices 108, 110,112, 114, 116, and 140 and/or the relay modules 102 may includecomponents (e.g., non-transitory computer readable media, processors,etc.) that store and/or execute client software configured to supportspecific vintages and/or versions of the cellular communications modulesincluded in the relay modules 102.

As mentioned above, the relay modules 102 may communicate with radiocommunication devices 110, such as LMR two-way radios. Thus, in anembodiment, the relay modules 102 may be configured to support thefrequencies and/or modulation formats associated with various radiocommunication devices 110. For example, the relay modules 102 may beconfigured to support half-duplex or simplex communication formats inwhich the communications signals are received and transmitted on thesame frequency to support communications with a LMR two-way radio.

FIG. 2 is an illustration of an embodiment explosion-proof relay module102 mounted on helmet 225 suitable for use in explosive environments byemergency services personnel. The explosion-proof video and relay module102 may be mounted in a variety of locations on the helmet 225 via afastener 222 and/or other means. The fastener 222 may be attached to anon-conductive housing of the relay module 102 and configured to securethe relay module 102 to the helmet 225. For example, the fastener 222may include a fastening mechanism configured to engage a fastening unitattached to the helmet 225. In various embodiments, the fasteningmechanism may be fabric hook-and-loop fastener (e.g., VELCRO®, etc.),hook tape, loop tape, sliding-engaging fastener, straps, locking clips,mounting clips, and/or any other similar fastening mechanisms currentlyknown or which may be developed in the future.

The explosion-proof relay module 102 may be include, or may be coupled,to a selector switch 220, which may be any push button and/or rotaryswitch that may be actuated by a human user wearing thick or flameresistant gloves. The selector switch 220 may be implemented as a hardkey, a soft key, a touch key, or any other way of receiving user input.

FIG. 3 is an illustration of an embodiment explosion-proof relay module102. The relay module 102 may include communications circuitry forsending and receiving voice, data, video, and other similar information,an illumination source (e.g., light emitting diodes, etc.) 308, aselector switch 220, a camera 304, a lens cover 306, and a sealed caseor housing 302.

All of the electronics, wires, contacts, and metal elements of the relaymodule 102 may be included in the sealed case/housing 302. The sealedcase/housing 302 may be formed from non-conductive materials, such asplastics, rubbers, thermoplastics (e.g., poly-methyl-methacrylate orPlexiglas), etc. The sealed case/housing 302 may be formed to include ahermetic and/or airtight seal that isolates the electronics, wires,contacts, and metal elements of the relay module 102 (including thecamera 304 and illumination source 308) from the exterior atmosphere andoxygen in the air.

Any of a variety of known mechanisms, components, and techniques may beused to create the airtight seal around the non-conductive materials ofthe case/housing 302, including snap fits, compression fits, sealingrings, threaded fasteners (e.g., nylon screws) to provide sealingpressure, etc. By sealing all electronics and metal within anon-conductive case/housing 302, the potential sources of sparks and/orignition (e.g., electronics, metal, etc.) may be isolated from theexterior atmosphere, reducing the likelihood that they will cause anignition in explosive environments.

In an embodiment, the relay module 102 may include a camera 304configured to capture images and/or video information, which may berelayed to mobile devices 108, 110, 140, the local/small cell site 104,and/or the radio access node 120 in real-time or near real-time. Thecamera 304 may include a lens cover 306 that seals and isolates thecamera 304 from the exterior atmosphere. In various embodiments, thecamera 304 may include any or all of a day vision component, a nightvision component, an infrared component, a thermal imaging component, anactive illumination component, an image intensification component, alaser range gated imaging component, and/or any other imagingtechnologies currently known or which will be developed in the future.

In an embodiment, the relay module 102 may include a personalillumination module. The personal illumination module may include alight emitting diode (LED) and/or other sources of illumination. In anembodiment, the illumination source (e.g., LED, etc.) may be mountedbehind the camera 304 lens. In an embodiment, the illumination sourcemay be positioned so that the camera 304 lens will not impede theillumination capability of the illumination source. In an embodiment,the illumination source may be positioned so that the camera 304 lensprotects the illumination source. In various embodiments, theillumination source and/or the camera 304 lens may be positioned insideof the sealed case/housing 302 and/or to form part of the hermetic sealaround the sealed case/housing 302.

FIG. 4 illustrates various logical and functional components that may beincluded in an embodiment relay module 102. The relay module 102 mayinclude a selector switch 220, a battery 406, a processor or centralprocessing unit (CPU) 408, charging circuitry 410, a radio-frequencyidentification (RFID) module 412, antennas 414 for sending and receivingelectromagnetic radiation, location sensors 416, a camera engine 418, anLED control module 420, a sensor engine 422, and other well knowncomponents (e.g., accelerometer, etc.) commonly included in modernelectronic devices (e.g., smartphones, mobile gaming consoles, etc.).The relay module 102 may also include multiple built-in low power and/orcellular radio systems, such as the illustrated Bluetooth/WiFi radios402 and LTE module 404, as well as any other low power and/or cellularradio systems currently available or which may be developed in thefuture.

The antennas 414 may be dual-polarized and/or employ any mounting ordesign technique currently known or which may be developed in thefuture. In various embodiments, the antennas 414 may be oriented tooptimize communications between the relay module 102 and the local/smallcell site 104, mobile devices, 108, 110, 140, radio access node 120and/or commercial/private communication systems.

In an embodiment, the location sensors 416 and/or the LTE module 404 mayinclude a global positioning system (GPS) receiver configured to receiveGPS signals from GPS satellites to determine the geographic position ofthe relay module 102.

One of the challenges associated with using GPS and other geo-spatialpositioning technologies on the relay module 102 is that the relaymodule's 102 ability to acquire satellite signals and navigation data tocalculate its geospatial location (called “performing a fix”) may behindered when the relay module 102 is indoors, below grade, and/or whenthe satellites are obstructed (e.g., by tall buildings, etc.). Forexample, the presence of physical obstacles, such as metal beams orwalls, may cause multipath interference and signal degradation of thewireless communication signals when the relay module 102 is indoors. Asanother example, the relay module 102 may not have sufficient access tosatellite communications (e.g., to a global positioning systemsatellite) to effectively ascertain its current location. In addition,the position accuracy afforded by existing technologies is notsufficient for use in emergency services due to the relatively highlevel of position accuracy required by these services.

For these and other reasons, GPS technologies may not always beavailable or suitable for use by the relay module 102. Accordingly, inan embodiment, the location sensors 416 may include accelerometers,gyroscopes, magnetometers, pressure sensors, and/or other sensors fordetermining the orientation and/or geographic position of the relaymodule 102, such as sensors for determining the radio signal delays(e.g., with respect to cell-phone towers and/or cell sites), performingtrilateration and/or multilateration operations, identifying proximityto known networks (e.g., Bluetooth® networks, WLAN networks, WiFi,etc.), and/or for implementing other known location-based technologies.In an embodiment, the location sensors 416 may include one or moresensors 309 for monitoring physical conditions (e.g., direction,motion/acceleration, orientation, pressure, etc.) on or around the relaymodule 102. In an embodiment, the relay module 102 may include multipleand/or redundant sensors (e.g., two gyroscopes, two accelerometers,etc.) for improved reliability, more accurate measurements, and/orrefined positional fixing.

In various embodiments, the relay module 102 may be configured to usethe location information collected by the location sensors 416 forrefined positional fixing and/or positional tracking in locations whereGPS signals are not available or determined to be unreliable. The relaymodule 102 may send location information collected by the locationsensors 416 to the local/small cell site 104, mobile devices, 108, 110,140, and/or radio access node 120. The relay module 102 may also computeits current location based on information collected by the locationsensors 416, and send its computed location information to thelocal/small cell site 104, mobile devices, 108, 110, 140, and/or radioaccess node 120.

In various embodiments, the relay module 102 may be configured togenerate or compute enhanced location information, which may be achievedvia one or more of the techniques disclosed in U.S. patent applicationSer. No. 13/491,915 titled Method and System for Providing EnhancedLocation Based Information for Wireless Handsets filed on Aug. 14, 2012,the entire contents of which is hereby incorporated by reference. Insuch embodiments, the location sensors 416 may collect or generatelocation information about the relay module 102 for refined positionalfixing and/or positional tracking in locations where GPS signals are notavailable or reliable.

The processor/CPU 408 of the relay module 102 may be configured toreceive processor-executable software instructions, which may includedin communication signals transmitted by the radio access node 120, thelocal/small cell site 104, the local incident command using a localterminal 116, handheld computer 114, and/or any other network component.The processor/CPU 408 may implement the received instructions to changeor update the operations of the relay module 102. For example, theprocessor/CPU 408 may receive instructions from the handheld computer114 and execute/implement the received instructions to change the typeof information (e.g., video, voice, or telemetry) collected and/orrelayed by the relay module 102. In this manner, a local incidentcommander may control what types of information are collected by therelay modules 102 and/or what types of information are made available tothe networked components (e.g., handheld computer 114, mobile devices,etc.).

The processor/CPU 408 may also be configured to send and receiveinformation to and from other electronic devices in close proximity tothe relay module 102. For example, the processor/CPU 408 may beconfigured to receive information from an oxygen sensor worn by a firstresponder at the incident scene, and determine whether additionalconditions should be monitored and/or whether additional informationshould be collected by the relay module 102 based on the informationreceived from the oxygen sensor. The relay module 102 may communicatethe received oxygen sensor information and informationcollected/generated in response to receiving the oxygen sensorinformation to any networked component (e.g., handheld computer 114,mobile devices, etc.) and/or display the information on an electronicdisplay coupled to the relay module. In this manner, the relay module102 may be configured detect a changing situation requiring theattention of a relevant actor (e.g., a person wearing the relay module,emergency personnel, the local incident commander, etc), and inform therelevant actor of the changing situation.

In an embodiment, the relay module 102 may be configured to send,receive, and/or relay information to other relay modules 102 and/orselected devices via a radio frequency link, which may be controlled bythe radio-frequency identification module 412. In an embodiment, therelay modules 102 may update or adjust their operations based on theinformation received from other relay modules 102 over the radiofrequency link. For example, a first relay module 102 may be configuredto send biometric information collected by the sensors 416 to a secondrelay module 102 over a radio frequency link. In this manner, relaymodules 102 within the same vicinity or explosive environment may remaininformed of the conditions (e.g., current air supply, heart rate, bodytemperature, battery status, etc.) associated with the other relaymodules 102 and/or users of the other relay modules 102, and adjusttheir operations accordingly.

In an embodiment, the relay module 102 may communicate with other relaymodules and/or any RF, WiFi or Bluetooth enabled device via the RFID 412and/or WiFi/Bluetooth 402 modules. For example, in an embodiment, therelay module 102 may receive information from medical equipment and/orother devices capable of sharing telemetry information via the RFID 412and/or WiFi/Bluetooth 402 modules, and update or adjust its operationsbased on the received information.

In an embodiment, the relay module 102 may include components (e.g.,non-transitory computer readable media, processor, etc.) that storeand/or execute client software. In an embodiment, the client softwaremay be tailored for the type of environment in which the relay module102 is deployed. In an embodiment, the relay module 102 mayautomatically detect environment in which is deployed, and automaticallymodify the client software functionality and/or relay module 102functionality to match the detected environment.

In an embodiment, the relay module 102 may include a camera engine 418configured to control one or more cameras of the relay module 102, whichmay include a standard camera, a night vision camera, an infraredcamera, or any other camera currently available or which may bedeveloped in the future.

In an embodiment, the relay module 102 may configured to adjust thequality and/or resolution of the images and video information collectedby the camera of the relay module 102. In an embodiment, the relaymodule 102 may configured to adjust the quality and/or resolution of thevideo feeds transmitted from, or received by, the relay module 102. Inan embodiment, the relay module 102 may be configured to adjust thequality and/or resolution of the videos and/or video feeds based on thedetected environmental or network conditions, situation awareness,and/or instructions received from the radio access node 120, thelocal/small cell site 104, the local incident command using a localterminal 116, a handheld computer 114, etc.

In an embodiment, the relay module 102 may include an LED control 420module configured to control one or more LEDs or illumination sources ofthe relay module 102. In an embodiment, the LEDs or illumination sourcesof the relay module 102 may be arranged so that they may be quicklyreplaced with other sensors, depending on the particular applicationand/or environment in which relay module 102 is deployed.

In order to reduce the potential sources of arching that could cause anexplosion, the relay module 10 may be powered by an internal battery406. The internal battery 406 may include one or more rechargeable ornon-rechargeable batteries. Since rechargeable batteries do not requirefrequent replacement, their inclusion in the relay module 102 mayeliminate or reduce the frequency in which the housing is opened and/orthe frequency in which the air-tight seal is broken. In variousembodiments, the relay module 102 may include any type of rechargeablebattery currently known or which may be developed in the future,including nickel cadmium, nickel hydride, nickel-metal hydride, orlithium-ion batteries.

To eliminate external metal contacts (which could serve as an ignitionsource), the relay module 10 may include charging circuitry 410, whichmay be configured to fit into, and receive power from, a chargingreceptacle. In an embodiment, charging circuitry 410 may be configuredto recharge the battery 406 using an induction charging system, whichmay be powered by the charging receptacle. Details regarding theinduction charging system and charger are described more fully belowwith reference to FIG. 9.

FIG. 5 illustrates various components of an embodiment relay module 102in which the cameras, sensors, and illuminations sources are housedtogether. In example illustrated in FIG. 5, the relay module 102includes a selector switch 220, a battery 406, charging circuitry 410, aradio-frequency identification (RFID) module 412, location sensors 416,a camera engine 418, a power plug 502, control circuitry 504,communications electronics 506, cameras 508, sensors 510, LEDs 512, areflector 514, a lens 516, and a lens cover 518.

The cameras 508, sensors 510, and LEDs 512 may be housed together andmounted on the reflector 512. The lens cover 518 may be arranged so asto help seal the relay module 102 and/or protect the electronics. In anembodiment, reflector 512 may be arranged so as to reduce or minimizethe amount of power required for LED's 512 to provide sufficient lumensfor vision capability. In an embodiment, reflector 512 may be arrangedso as to reduce the current draw of the relay module 102, and thusreduce the power consumption, battery weight, and/or physical dimensionsof the relay module 102.

The cameras 508 may include video cameras and still image cameras. Thecameras 508 and LED's 512 may be arranged to capture both visible andnear infrared portions of the electromagnetic spectrum present aroundthe relay module 102.

In various embodiments, the LED's 512 may be controlled by a processorof the relay module 102 and/or a remote device. In embodiment, the LED's512 may be configured to have a pulsed-duty cycle, which may reduce theamount of current draw and extend the battery life of the relay module102. In an embodiment, the pulsed-duty cycle of the LED's 512 may bevariable. In an embodiment, pulsed-duty cycle of the LED's 512 may bevaried by a processor of the relay module 102 and/or a remote deviceand/or based on the intensity of illumination required for a particularuse, application, location, position, or environment.

FIG. 6 is an illustration of front and side portions of an embodimentrelay module 102. In example illustrated in FIG. 6, the relay module 102includes a video camera 508, a sensor 510, and LEDs 512 mounted on areflector 512, all of which are encapsulated in a sealed case or housing302. A fastener 222 attached to the housing 302 may be used to fastenthe relay module 102 onto a helmet or other equipment.

The video camera 508 may be positioned in the center of the front of therelay module 102. A plurality of LEDs 512 may be arranged around thevideo camera 508. The LEDs 512 may generate electromagnetic radiation inthe visible and/or near infrared spectrum arranged. The sealedcase/housing 302 may be a cylindrical or rectangular in shape or acombination of cylindrical and rectangular to facilitate the inclusionof all the electronics to meet the required form factor for a lowprofile explosion proof video and communications relay module 102.

While FIG. 6 illustrates one example configuration, it should beunderstood that the arrangement the LEDs 512, camera 508 and/or sensor510 illustrated in FIG. 6 is exemplary and not intended to limit theinvention to specific arrangement or configuration.

FIG. 7 is an illustration of rear and side portions of an embodimentrelay module 102. In example illustrated in FIG. 7, the relay module 102includes a battery charging adaptor 702, which may be circular in designand/or designed to a charging base.

FIG. 8 is another illustration of rear and side portions of anembodiment relay module 102 in which a charging receptacle 704 thebattery charging adaptor 702 is rectangular or square, which mayfacilitate a better mechanical fit and structural integrity for therelay module 102.

FIG. 9 illustrates components that may be included in another embodimentexplosion proof video and communications relay module 902 suitable foruse by personnel working in conjunction with others who are in anexplosive environment and may or may not be required to enter theexplosive environment. The relay module 902 may be mounted to a user'shead or helmet, or may be positioned on a stationary platform forcontinuous remote monitoring.

The relay module 902 may include communications circuitry for sendingand receiving voice, data, video, and other similar information, anillumination source (e.g., light emitting diodes, etc.), a selectorswitch 304, cameras 508, a lens 516, a lens cover 518, LEDs 512, sensors510, a sealed case or housing 302, and any or all the other componentsthat may be included in the relay module 102 discussed above.

As discussed above, all of the electronics, wires, contacts, and metalelements of the relay module 902 may be included in the sealedcase/housing 302, which may formed from non-conductive materials, suchas plastics, rubbers, thermoplastics (e.g., poly-methyl-methacrylate orPlexiglas), etc. The sealed case/housing 302 may be formed to include ahermetic and/or airtight seal that isolates the electronics, wires,contacts, and metal elements of the relay module 902 from the exterioratmosphere.

The relay module 902 may include a strap 904 for fastening the device tothe user's head or helmet. The strap 904 may be formed from an elasticmaterial or any other material suitable for fastening the device to theuser's head or helmet. The strap 904 may include an adjustment 906 meansor mechanism for securing the relay module 902 user's head or helmet.

The selector switch 304 may be a push button or rotary or any type ofselector which can turn on the unit and provide the functionality neededfor someone wearing gloves. The selector switch 304 may be mounted onthe top, front, or the side of the relay module 902.

In the example illustrated in FIG. 9, the housing 302 for explosionproof video and communications relay module 902 is depicted as beingrectangular. In an embodiment, the case/housing 302 may be cylindricalor a combination of cylindrical and rectangular to facilitate theinclusion of all the electronics to meet the required form factor for alow profile relay module 902.

FIG. 10 illustrates various logical and functional components that maybe included in an embodiment relay module 902. The relay module 902 mayinclude a selector switch 220, a battery 406, Bluetooth/WiFi radios 402,an LTE module 404, a processor or central processing unit (CPU) 408,charging circuitry 410, a radio-frequency identification (RFID) module412, antennas 414 for sending and receiving electromagnetic radiation,location sensors 416, a camera engine 418, an LED control module 420, asensor engine 422, a P25 radio 422, and other well known components(e.g., accelerometer, etc.) commonly included in modern electronicdevices (e.g., smartphones, mobile gaming consoles, etc.). The relaymodule 902 may also include a communications electronics 506, cameras508, LEDs 512, a reflector 514, a lens 516, a lens cover 518, and any orall the other components that may be included in the relay module 102discussed above.

FIG. 11 is an illustration of a front portion of an embodiment relaymodule 902. In example illustrated in FIG. 11, the relay module 102includes a selector switch 304, a battery 406, antennas 414, a videocamera 508, a sensor 510, LEDs 512, and a reflector 514, all of whichmay be encapsulated in a sealed case or housing 302.

FIG. 12 illustrates that an adjustment 906 mechanism may be attached toeach side of the housing 302 and operable to secure the relay module 902user's head or helmet.

FIG. 13 is an illustration of a bottom portion of the relay module 902illustrating the location of the charging adaptor 704 in accordance withan embodiment. The charging adaptor 704 may be configured to interfacewith a charging base to charge the battery 406, which may be achievedvia induction. The charging adaptor 704 may be also be configured to fitinto a charging receptacle in the charging base, as described in moredetail further below.

The relay modules 102 may be configured to operate as a standalonedevices. The relay modules 102 may also be grouped with other devicesfor collaborative communication in which one or more of the relaymodules may operate as an access point for other relay modules or otherwireless devices.

FIG. 14 illustrates an embodiment method 1400 for the initializing andauthenticating a plurality of relay modules, grouping the relay moduleswith other explosion relay modules, and confirming the groupings. Whenenergized, each of relay modules 1401, 1402, 1403 and 1404 mayimmediately scan the airwaves for defined and preferred radio frequency(RF) carriers and systems. For example, after relay module 1401 ispowered on, it may scan the airwaves for predefined and/or preferredradio frequency carriers and/or systems with which the relay module 1401may connect to the network. If the relay module 1401 does not find anappropriate network with which it may connect (or loses its connection)the relay module 1401 may scan the airwaves for other radio accesssystems (e.g., mobile network, radio access point associated with amobile device, etc.) to acquire (i.e., connect to) until a connection toa network/Internet is established. These operations may also beperformed in the event of a dropped call or power interruption.

The relay module 1401 may also begin acquiring GPS signals whilescanning the airwaves for radio frequency carriers and/or systems. Ifthe relay module 1401 cannot acquire GPS signals, a network component(not illustrated) may help determine the relative position of the relaymodule 1401 based on one or more of the location determination solutionsdiscussed herein (e.g., based on the antenna used for the radio accesspoint, the time delay, angle of arrival, etc.).

The relay module 1401 may acquire (i.e., connect to) an appropriateradio access system, radio frequency carrier and/or system via themobile device's system acquisition system and establish a connection toa network via an eNodeB (eNB1 or eNB2) or any other communicationtechnologies discussed above.

After the relay module 1401 acquires the radio access system, thenetwork (i.e., a component in the network such as a server) will knowthe approximate location of the relay module 1401 (e.g., via one or moreof the location determination solutions discussed above, such asproximity to base towers). In addition, the relay module 1401 maycompute its current location (e.g., via GPS and/or the locationdetermination solutions discussed above), store the computations in amemory of the mobile device, and report its current location to thenetwork.

In addition to knowing the approximate location of the relay module1401, the network may also be informed of the locations of other relaymodules 1402, 1403, 1404 and the proximity of the other relay modules1402, 1403, 1404 to the recently acquired relay module 1401.

After initialization and authentication, the relay modules may beinstructed to be grouped by the network. Relay modules 1401 and 1402 mayinitiate sharing of information for position location, either due to thenetwork driven grouping request or when the relay module has lostcontact with the network and attempts to find a suitable relay module tohelp in its position location and possible connection to the network viaa relay or to another network.

Relay module 1401 may send a request for position information to relaymodule 1402. The information may be sent after the authenticationprocess between relay modules, and may include a time stamp. The timestamp may be sub seconds in size (e.g., milliseconds). The relay module1402 may respond with a message that also has a time stamp, and timinginformation pertaining to when the relay module 1402 received the timestamp from relay module 1401. Three messages may be transferred quicklyto establish time synchronization. The time differences may then becompared, along with possible pulses or pings, to establish an estimateddistance vector between the relay modules. Knowing the distance vectorand the x, y, and z coordinates of both 1401 and 1402, a point-to-pointfix may be established.

The relay module 1401 may then initiate communication with relay modules1403, 1404 and repeat the operations discussed above with respect torelay module 1402 for each of relay module 1403, 1404. After obtainingtwo or more distance vectors along with positional information, therelay module 1401 may compare the new coordinates to its previouslycomputed current location, and adjust the location computationsaccordingly.

The positional information distance vectors may be sent to the networkfor positional processing with other network positional information.Based on the position calculated for the relay module, the network(i.e., a component in the network, such as a network server or E-SMLC)may instruct the relay module to adjust its positional information.

Additionally the relay module 1401 may also make a positional correctionif the network either does not respond in time, which may result in amessage update time out. Alternatively, when the network cannot make thenecessary correction, and the positional information may used by anothercomponent and/or other relay modules to perform the necessarycorrections.

If the error is greater than x % for a lower positional confidence levelthen no update is required. As the mobile receives other sensor data andmore than a pre-described distance in any direction or a combineddistance vector than the positional update process begins again. If thex % of positional confidence level is less than desired, additionalpositional updates may be made with the grouped relay modules (e.g.,iteratively) to improve the confidence level of the positionalinformation. Additionally if the positional information from one of therelay modules that is being attempted to obtain a distance vectorappears to be in error, then that relay modules data may be selected tonot be used for this iterative step of performing positional updateswith other grouped relay modules. However it will continue to be queriedas part of the process since its position location could be corrected inone of the steps it is taking to improve its position location as well.

Additionally in the event that one or more relay modules losecommunication with the core network it will still be possible tomaintain position accuracy through one of the other grouped relaymodules. It will also be possible to continue to maintain acommunication link by establishing a network relay connection withanother of the relay modules in the same group which still hascommunication with the network itself.

In various embodiments, the relay modules 1401, 1402, 1403 and 1404 maybe grouped based on their proximity to each other and/or a groupingplan, which may be stored in the memory of the relay modules, in anetwork component, or a remote mobile device. In addition, the networkmay, based on policy and rules pre-established or defined by theincident commander, instruct all the relay modules 1401, 1402, 1403 and1404 to form a local network. This may be achieved by a networkcomponent or a remote mobile device assigning a first relay module 1401as a master relay module so that the assigned master relay module 1401operates as a router to manage all communications between the wirelessnetwork and the other relay modules 1402, 1403, 1404 in the group.

FIG. 15 illustrates an embodiment method 1500 for performing group relayoperations for relaying telemetry information to a plurality of relaymodules. In blocks 1502 and 1504, the relay modules 1401, 1402, 1403,and 1404 may perform initialization, authentication, and groupingoperations, as discussed above with reference to FIG. 14. In block 1506,the location server may send group relay instructions to any or all ofthe relay modules 1401, 1402, 1403, and 1404. In the example illustratedin FIG. 15, the group relay instructions designate the relay module 1401as the master relay module, which establishes a data connection to thenetwork via an eNodeB (eNB).

In block 1508, relay module 1401 establishes a near field local areanetwork (NR LAN) with the grouped relay modules 1402, 1403, 1402, andtakes on a master role in the established NR LAN. Each of the groupedrelay modules 1402, 1403, 1402 may send telemetry information (includingvoice, data and video) to the master relay module 1401, which relays thetelemetry information to appropriate component over the network via theeNodeB (eNB).

In an embodiment, the relayed telemetry information may includepositional information, bio-sensor information, user bio-information,environmental information, user condition information, and/or any otherinformation that may be available to the relay modules 1401, 1402, 1403,1404.

FIG. 16 illustrates an embodiment relay module method 1600 forreestablishing lost communications links and performing group relayoperations to relay telemetry information. In blocks 1502 and 1504, therelay modules 1401, 1402, 1403, and 1404 may perform initialization,authentication, and grouping operations, as discussed above withreference to FIGS. 14 and 15. In block 1602, relay module 1402 maydetermine that it has lost its connection to the eNodeB (eNB) and can nolonger can access the communications network. As part of block 1602, therelay module 1402 may begin scanning the airwaves for another radiosaccess system to acquire.

In block 1604, a location server (e.g., E-SMLC) may determine that itcan no longer communicate directly with relay module 1402, and send thelast known position of the relay module 1402 to the other relay modules1401, 1403, 1404 along with group relay instructions that designate therelay module 1401 as the master relay module. In block 1606, relaymodule 1401 establishes a near field local area network (NR LAN) withthe grouped relay modules 1402, 1403, 1402, and takes on a master rolein the established NR LAN.

The relay module 1402 may send location and telemetry information(including voice, data and video) to the master relay module 1401. Themaster relay module 1401 may relay the received location and/ortelemetry information to the location server (e.g., E-SMLC), which mayuse the received information to reestablish a communication link withthe relay module 1402. The master relay module 1401 may also relay thetelemetry information to appropriate component over the network via theeNodeB (eNB) until, for example, the lost communication link isreestablished.

FIG. 17 is an illustration of an example charging receptacle 1700 andcharging circuitry 410 the relay module 102 suitable for recharging thebattery 406. The recharging power may be provided by an induction coil1701 positioned within or adjacent to the charging receptacle 1700 andcoupled to a rectifier and charge control circuit 1702. Energy may betransferred by induction from induction coil 1701 to charge controlcircuit 1702, which may ensure that the housing for the explosion-proofvideo and communication relay module 102 does not expose wires,electronics, or metal contacts to the atmosphere.

The charging receptacle 1700 may be powered by an alternating current(AC) or direct current (DC) source 1704. In an embodiment, the chargingreceptacle 1700 may be configured to use both AC and DC power as thesource 1704. In an embodiment, the charging receptacle 1700 may includea DC to AC switching rectifier configured to convert the DC voltage toAC voltage.

In order to ensure the explosion-proof communication relay module 102 issafe to operate in an explosive environment, the internal circuitry mayinclude various safety features which may not be required in othercommunication devices. These safety features may include fault isolationcircuit elements, such as sealed fuses 1706, which may isolate thebattery 406 from a fault in the event of a short-circuit or similarfault. The relay module 102 any of a variety of other known faulttolerant circuit elements 1710 in addition to, or instead of, the sealedfuses 1706. The fault tolerant circuit elements 1710 may be configuredto ensure that a short circuit cannot generate a temperature high enoughto ignite explosive vapors.

In addition to the fault tolerant circuit elements 1710 and self actingisolation circuitry such as fuses 1706, the processor/CPU 408 may beconfigured with software to monitor voltage and current through avariety of circuit elements 1708 and activate cut off switches or relaysthat can isolate overheating or faulted circuitry.

The explosion-proof video and communication relay module 102 may alsoinclude internal temperature sensors, such as thermistors 1720configured to monitor the temperature of the battery 406 and otherinternal electronics. For example, most rechargeable batteries generateheat during the charge or discharge cycle. By using temperatureindicating readings received from a thermistor 1720 coupled to thebattery 406, the processor 408 may monitor charging and dischargingcycles, such as to terminate charging once the battery reaches a fullycharged or elevated temperature condition.

Additionally, the processor 408 may monitor battery temperature toassess the condition of the battery to protect against the possibilityof overheating or explosion as has been known to occur in some batterytypes. The processor 408 may be configured with software to present analarm to users when the battery temperature or performance indicatesthat the battery 406 poses a threat of overheating or fire. Similarly,the processor 408 may monitor internal temperatures using otherthermistors 1720 to determine whether any of the electronics areoverheating or if the module itself is in a overheat condition, such asin the presence of external fire. The processor 408 may also beconfigured to take preventative actions to limit damage to the module inthe event of overheating, including generating audible or visual alarmsor transmitting signals via one or more of the antennas 414.

FIG. 18 is an illustration of a charging base 1800 suitable for use withthe various embodiments. The charging base 1800 may include a powerinput 1802, which may be both an AC and DC power source, depending on anexternal plug 1804 used to facilitate one or both AC and DC inputs. Thecharging base 1800 may include power control circuitry 1806 configuredto provide the required AC voltage to the inductors for induction powertransfer. The charging base 1800 may also include a fusible link 1808configured for use in over voltage conditions and LED lights to indicatethe charging state.

FIG. 19 is an illustration of a top portion of a charging base 1800suitable for use with the various embodiments. The charging base 1800may include induction coils 1902 positioned in proximity to a receivingportion 1904 so as to charge the battery 406 of the relay module 102. Inan embodiment, the induction coils 1902 may be positioned to facilitatemaximum power transfer to the relay module 102.

FIG. 20 is an illustration of a top portion of another charging base1800 suitable for use with the various embodiments. In the exampleillustrated in FIG. 20, the induction coils 1902 may be shaped andpositioned to facilitate maximum power transfer to the relay module 102.

FIG. 21 is an illustration of a top portion of yet another charging base1800 suitable for use with the various embodiments. In the exampleillustrated in FIG. 21, the induction coils 1902 may be shaped andpositioned to facilitate maximum power transfer to the relay module 102.

In an embodiment, the relay modules 102 may be coupled to microphoneand/or speaker (e.g., via Bluetooth) to facilitate voice communicationswith mobile devices, network components and other relay modules 102.

FIG. 22 illustrates that the relay module 102 may include an audiocircuit 2206 configured to control a microphone 2202 and speaker 2204from within the hermetically sealed relay module 102. Input and outputto and from the microphone 2202 and speaker 2204 may communicated via anear field communications radio, such as a Bluetooth radio 402. The CPU402 may control the audio circuit 2206 to control the audio informationsent and/or received from the microphone 2202 and speaker 2204.

In the example illustrated in FIG. 22, the microphone 2202 is attachedto a strap 2203 that may be worn by personnel entering into an explosiveenvironment. In an embodiment, the strap 2202 may be adjustable. In anembodiment, the microphone 2202 and/or speaker 2204 may include amounting clip made of non conductive material so that they may be wornby personnel in an explosive environment.

FIG. 23 illustrates various components commonly included in a mobiletransceiver device 2300 and suitable for use as a relay module or amobile device in various embodiments. A typical mobile transceiverdevice 2300 include a processor 2301 coupled to internal memory 2302, adisplay 2304, and to a speaker 2306. In addition, the mobile transceiverdevice 2300 may include an antenna 2308 for sending and receivingelectromagnetic radiation that may be connected to a wireless data linkand/or cellular telephone transceiver 2310 coupled to the processor2301. Mobile transceiver devices 2300 also typically include menuselection buttons or rocker switches 2310 for receiving user inputs.

A typical mobile transceiver device 2300 also includes a soundencoding/decoding (CODEC) circuit 2312 which digitizes sound receivedfrom a microphone into data packets suitable for wireless transmissionand decodes received sound data packets to generate analog signals thatare provided to the speaker 2306 to generate sound. Also, one or more ofthe processor 2301, transceivers 2310, and CODEC 2312 may include adigital signal processor (DSP) circuit (not shown separately). Themobile transceiver device 2300 may further include a peanut or a ZigBeetransceiver (i.e., an IEEE 802.15.4 transceiver) 2314 for low-powershort-range communications between wireless devices, or other similarcommunication circuitry (e.g., circuitry implementing the Bluetooth® orWiFi protocols, etc.).

Various embodiments may be implemented on any of a variety ofcommercially available server devices, such as the server 2400illustrated in FIG. 15. Such a server 2400 typically includes one ormore processors 2401, 2402 coupled to volatile memory 2403 and a largecapacity nonvolatile memory, such as a disk drive 2404. The server 2400may also include a floppy disc drive, compact disc (CD) or DVD discdrive 2406 coupled to the processor 2401. The server 2400 may alsoinclude network access ports coupled to the processor 2401 forestablishing data connections with a network 2405, such as a local areanetwork coupled to other communication system computers and servers.

The processors 2301, 2401 and 2402 may be any programmablemicroprocessor, microcomputer or multiple processor chip or chips thatcan be configured by software instructions (applications) to perform avariety of functions, including the functions of the various embodimentsdescribed below. In some mobile devices, multi-core processors 2402 maybe provided, such as one processor core dedicated to wirelesscommunication functions and one processor core dedicated to runningother applications. Typically, software applications may be stored inthe internal memory before they are accessed and loaded into theprocessor 2301, 2401 and 2402. The processors 2301, 2401 and 2402 mayinclude internal memory sufficient to store the application softwareinstructions.

The various embodiments may be implemented in, or make use of, a varietyof commercial cellular networks, including LTE, CDMA, and/or GSMcellular networks. Various embodiments may make use of differentimplementations of these basic cellular technologies, including WCMDA,TD-CDMA, and TD-SCDMA. In addition, various embodiments may make use ofany of a wide variety of wireless cellular data network protocols (e.g.,WiFi, WiMAX, Bluetooth, etc.), near field communication technologies(e.g., peanut, ultrawideband, whitespace communication, etc.), and/orradio communication technologies (e.g., land mobile radio or “LMR”and/or Project 25 or “P25” wireless access technologies).

Mobile devices may be configured to communicate with a radio accessnode, which may include any or all of wireless base station, radioaccess point, components for establishing communication links to variousnetworks, including LTE, CDMA2000/EVDO, WCDMA/HSPA, IS-136, GSM, WiMax,WiFi, AMPS, DECT, TD-SCDMA, TD-CDMA, a switch, Land Mobile Radio (LMR)interoperability equipment, a Fixed Service Satellite (FSS) (e.g., forremote interconnection to the Internet and PSTN), and other similarcomponents.

The various embodiments may be described with reference to specificfrequencies, including the 700 MHz LTE band, the 450 MHz, 700 MHz, 850MHz bands, the 1710-1755 MHz and 2110-2155 MHz AWS bands (as well asfuture AWS bands), and the 1.8-1202 GHz PCS band, etc. In addition,various embodiments may be described with reference to specific LTEfrequencies. However, the various embodiments may make use of any or alltechnologies, frequencies, and mobile cellular bands currently in use orwhich may be employed in the future. By way of example, variousembodiments may be implemented with cellular wireless networks thatoperate at different frequencies, such as WiFi and WiMAX. Thus, itshould be understood that references to particular frequencies ortechnologies are for illustrative purposes only, and not intended tolimit the scope of the invention or the claims to particularfrequencies, bands or cellular communication protocols unlessspecifically recited in the claims.

References to cellular telephones in the descriptions of the variousembodiments are not intended to exclude other communication devices andtwo-way radios.

Flashlights are prevalent devices and are used extensively to aid insituation awareness.

Mobile devices may include a subscriber identification module (SIM)hardware, memory, or card that stores one or more encoded values thatidentify the mobile device's home network. In various embodiments, themobile device SIM may be a virtual SIM, a removable user identity module(R-UIM), a Mini SIM, a MicroSIM, a universal subscriber identity module(USIM) or any other similar identity module.

Generally, when a mobile device's home network is not available, themobile device may traverse a preferred roaming list (PRL) to identify avisitor network through which the mobile device may connect to theglobal telecommunication network. In the various embodiments, a mobiledevice may include a system acquisition function configured to useinformation contained in the SIM or PRL to determine the order in whichlisted frequencies or channels will be tried when the mobile device isto acquire (i.e., connect to) a wireless network system (also referredto as a network or communication network). A mobile device may attemptto acquire network access (i.e., locate a channel or frequency withwhich it can access a wireless network) at initial power-on or when acurrent channel or frequency is lost for a variety of possible reasons.

The widespread use of cellular telephone communications makes suchmobile devices ideal for many ad hoc communication situations. Cellulartelephones, flashlights and video cameras are not designed, however, tooperate in explosive environments, so lack fault tolerance circuitry,and have exposed metal contacts which could serve as spark initiators.Therefore, anyone entering potentially explosive environments must forgohis or her conventional cellular telephones and flashlights and otherelectronics like video capture and relay devices.

The various embodiments overcome the limitations of personal lighting,real time video transfer, and cellular telephone and other mobilewireless communication systems to enable their use in explosiveenvironments, including the ability to relay cellular communicationsdeep into building and underground facilities where cellular signalscannot normally reach. A portable explosion-proof video andcommunication system is provided and features a hermetically-sealedcasing that encompasses all circuit and metal contacts, fault-tolerantelectrical circuitry, an induction charging module for recharginginternal batteries without the need for any exposed metal contacts, anda power management algorithm that maintains output power at the lowestlevel that can provide adequate communications. In order to complete thevideo and communication system, an explosion-proof video and mobilecommunication device, such as a cellular telephone, and a personalillumination device is provided, which is hermetically sealed andincludes fault-tolerant circuitry and an induction charging module forrecharging internal batteries without the need for any exposed metalcontacts. As a further embodiment, a nonmetallic sealed container isprovided for, encompassing conventional mobile communication devices,such as cellular telephone handsets, real time video relay, and personalillumination device so that they can be taken into an explosiveenvironment.

The various embodiments provide explosion-proof video communicationsystem modules and explosion-proof mobile devices, such as cellulartelephones, real time video relay modules, and personal illuminationmodules that are configured for safe operation in an explosiveenvironment and extend the reach of a communication network, such as acellular telephone network.

The explosion-proof video and communications relay module 102 mayreceive information from the sensor module 122 or through thecommunications network, either from the cloud 130 or from the localcomputer/server 13. Emergency medical services 132 can also use anexplosion-proof communications relay module 11 and see the informationfrom any one of the video and communication relay modules. In addition,the communication device 11 can link with a hospital 129 from theambulance 126 or from the incident itself.

In order to meet the communication requirements to enhance situationawareness with intrinsic safe equipment it may be necessary to changesome of the communication equipment form factor for improvedfunctionality.

A number of hazardous work environments exist where conventionalcommunication systems are either impractical or cost prohibitive orboth.

Emergency services personnel using conventional communications equipmentface the risk of causing explosions when they must enter collapsedbuildings, underground passage ways and subways, or vehicle or aircraftaccident scenes where explosive vapors may be generated or accumulate.In such situations emergency services personnel need effective andefficient communication means to coordinate with others, call in medicalassistance, or seek advice from commanders and technicians positionedoutside the danger area. Conventional communications systems may not befeasible, however, due to their potential to initiate an explosion ifused in explosive environments.

The capabilities of cellular communications and in particular smartphones make it possible to extend broadband to the edge of the networkboth for public and private wireless systems. With Broadband to the endof the network it is now possible to have mission-critical informationthat can be accessed and displayed through cellular communicationstechnology thereby improving situation awareness and responsiveness.

Additionally it is now possible to have video and other data telemetryinformation besides voice communications sent to other cellular devices.It is also possible to have the video and other telemetry informationsent to the incident command so that one can be aware of what thepersonnel in the explosive environment are actually seeing.

The explosion-proof video and communication relay module may also becapable of operating as an intrinsically safe flashlight so as tominimize the amount of equipment personnel entering the environment needto have donned.

To minimize the risk of explosion in such dangerous situations, it iscritical that all equipment used by workers who must venture into suchenvironments be designed to remove all possible ignition sources.Electrical equipment, even low voltage equipment, is of particularconcern due to the possibility of a spark generated by a shorted circuitthat may ignite a highly explosive environment. In addition,communication equipment has the potential of inducing voltages inexposed metal components which can also cause a spark under certaincircumstances.

Ideally, a communication system for use in explosive environments willbe able to provide data and voice communications that are scalable sothat the extent and range of communication coverage can grow and shrinkas the situation requires. In addition, it is desirable to have videoand communication equipment which is mobile so that the equipment can beeasily donned during a rescue operation and quickly doffed if needed. Itis also desirable to have video and communication equipment used bypersonnel in explosive environment is durable and cost efficient tooperate.

In most situations personnel entering a hazardous area need to donprotective equipment in order to enter those environments. SpecificallyFire Service, Hazmat and other personnel when donning protectiveequipment lose some mobility, functionality and visibility for situationawareness due to the protective equipment that is donned.

Preferably, a communication system would provide users with thenecessary mobility to move about while providing enhanced situationcommunication and situation awareness in hazardous environments.

The use of both day and night video cameras and of infrared cameras isbecoming more commonplace. Their ability to lend to situation awarenesshas led to many improvements in their use, especially in security, lawenforcement, surveillance and inspections.

The foregoing method descriptions and the process flow diagrams areprovided merely as illustrative examples and are not intended to requireor imply that the steps of the various embodiments must be performed inthe order presented. As one of skill in the art would appreciate, onemay perform the steps in the foregoing embodiments in any order.

Those of skill in the art will appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the embodiments disclosed herein that may be implementedas electronic hardware, computer software, or combinations of both. Toillustrate clearly this interchangeability of hardware and software,various illustrative components, blocks, modules, circuits, and stepshave been described generally above in terms of their functionality.Whether such functionality is implemented as hardware or softwaredepends upon the particular application and design constraints imposedon the overall system. Skilled artisans may implement the describedfunctionality in varying ways for each particular application, but suchimplementation decisions should not be interpreted as causing adeparture from the scope of the present invention.

The foregoing description of the various embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention. Thus, the present invention is notintended to be limited to the embodiments shown herein, and instead theclaims should be accorded the widest scope consistent with theprinciples and novel features disclosed herein.

In the foregoing descriptions of the various embodiments thecommunication systems are described as including explosion-proofcellular telephones 15 which may be any explosion-proof mobile device.One of skill in the art, however, will appreciate that theexplosion-proof communication relay modules 10 may be used withnon-explosion-proof mobile devices when not used in an explosiveenvironment. Thus, while the explosion-proof communication relay modules10 enable safe and effective communications in explosive environments,they will work equally effectively in non-explosive environments withany mobile devices (explosion-proof or not) that operate at compatiblecommunication frequencies.

The foregoing method descriptions and process flow diagrams are providedmerely as illustrative examples and are not intended to require or implythat the blocks of the various embodiments must be performed in theorder presented. As will be appreciated by one of skill in the art, theorder of blocks in the foregoing embodiments may be performed in anyorder. Words such as “thereafter,” “then,” “next,” and etc. are notintended to limit the order of the blocks; these words are simply usedto guide the reader through the description of the methods. Furthermore,any reference to claim elements in the singular, for example, using thearticles “a,” “an,” or “the” should not be construed as limiting theelement to the singular form.

The various illustrative logical blocks, modules, circuits, andalgorithm blocks described in connection with the embodiments disclosedherein may be implemented as electronic hardware, computer software, orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and blocks have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentinvention.

The hardware used to implement the various illustrative logics, logicalblocks, modules, and circuits described in connection with theembodiments disclosed herein may be implemented or performed with ageneral purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but, in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration. Alternatively, some blocks or methods may be performed bycircuitry that is specific to a given function.

In one or more exemplary aspects, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored as one or moreinstructions or code on a non-transitory computer-readable medium ornon-transitory processor-readable medium. The steps of a method oralgorithm disclosed herein may be embodied in a processor-executablesoftware module which may reside on a non-transitory computer-readableor processor-readable storage medium. Non-transitory computer-readableor processor-readable storage media may be any storage media that may beaccessed by a computer or a processor. By way of example but notlimitation, such non-transitory computer-readable or processor-readablemedia may include RAM, ROM, EEPROM, FLASH memory, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that may be used to store desired programcode in the form of instructions or data structures and that may beaccessed by a computer. Disk and disc, as used herein, include compactdisc (CD), laser disc, optical disc, digital versatile disc (DVD),floppy disk, and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofnon-transitory computer-readable and processor-readable media. Inaddition, the operations of a method or algorithm may reside as one orany combination or set of codes and/or instructions on a non-transitoryprocessor-readable medium and/or computer-readable medium, which may beincorporated into a computer program product.

The preceding description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention. Thus, the present invention is notintended to be limited to the embodiments shown herein but is to beaccorded the widest scope consistent with the following claims and theprinciples and novel features disclosed herein.

What is claimed is:
 1. An explosion-proof communication device,comprising: a non-conductive housing; a first antenna; a second antenna;a radio receiver; a radio transmitter; a battery coupled to a faulttolerant circuit element; and a processor coupled to the first antenna,second antenna, radio receiver, radio transmitter, and battery, whereinthe processor is configured with processor executable softwareinstructions to perform operations comprising: receiving radio frequencysignals from the first antenna via the radio receiver in one modulationformat; and retransmitting the received frequency signals from thesecond antenna via the radio transmitter in a second modulation formatthat is different than the first modulation format, and wherein theprocessor, first antenna, second antenna, radio receiver, radiotransmitter, battery, and fault tolerant circuit element arehermetically sealed inside the non-conductive housing.
 2. Theexplosion-proof communication device of claim 1, wherein the radioreceiver and radio transmitter comprises a signal generator configuredto generate a radio frequency signal having a third frequency.
 3. Theexplosion-proof communication device of claim 2, wherein the processoris configured with processor-executable software instructions to performoperation further comprising adjusting the frequency of the radiofrequency signal generated by the signal generator.
 4. Theexplosion-proof communication device of claim 1, wherein the processoris configured with processor-executable software instructions to performoperations further comprising controlling an output power of the radioreceiver and radio transmitter to maintain the output power at a minimumlevel consistent with a minimum quality of the service metric and belowa maximum output power level.
 5. The explosion-proof communicationdevice of claim 1, wherein the processor is configured withprocessor-executable software instructions to perform operations furthercomprising grouping the relay device with a wireless transceiver inproximity to the relay device to form a communication group, whereinreceiving radio frequency signals from the first antenna at a firstfrequency comprises receiving radio frequency signals from the wirelesstransceiver in the communication group.
 6. The explosion-proofcommunication device of claim 1, further comprising a fastener attachedto the non-conductive housing and configured to secure theexplosion-proof communication relay device to a helmet.
 7. Theexplosion-proof communication device of claim 6, wherein the fastenerincludes a strap.
 8. The explosion-proof communication device of claim6, wherein the fastener includes a fabric hook-and-loop fasteningelement.
 9. The explosion-proof communication device of claim 1, furthercomprising a selector switch coupled to the non-conductive housing andarranged so that it may be actuated by a human user wearing gloves tocause the processor to perform one or more operations.
 10. Theexplosion-proof communication device of claim 1, further comprising: acamera coupled to the processor; and a lens cover arranged to seal andisolate the camera from an exterior atmosphere.
 11. The explosion-proofcommunication device of claim 10, further comprising an illuminationsource mounted behind a camera lens of the camera and arranged so thatthe illumination capability of the illumination source is not impeded.12. The explosion-proof communication device of claim 10, wherein theprocessor is configured with processor-executable software instructionsto perform operations further comprising: receiving instructions from asecond explosion-proof communication relay device; and adjusting aresolution of video information collected by the camera based on thereceived instructions.
 13. The explosion-proof communication device ofclaim 1, further comprising a sensor hermetically sealed inside thenon-conductive housing and configured to monitor environmentalconditions outside the non-conductive housing.
 14. The explosion-proofcommunication device of claim 1, further comprising an audio circuithermetically sealed inside the non-conductive housing and configured tobe coupled to a microphone and a speaker outside of the non-conductivehousing from within the hermetically sealed non-conductive housing. 15.A communication system for use in an explosive environment, comprising:a first explosion-proof communication relay device and a secondexplosion-proof communication relay device, wherein each of the firstand second explosion-proof communication relay devices comprise: anon-conductive housing; a first antenna; a second antenna; a radioreceiver; a radio transmitter; a battery coupled to a fault tolerantcircuit element; and a processor coupled to the first antenna, secondantenna, radio receiver, radio transmitter, and battery, wherein theprocessor is configured with processor executable software instructionsto perform operations comprising: receiving radio frequency signals fromthe first antenna via the radio receiver in one modulation format; andretransmitting the received frequency signals from the second antennavia the radio transmitter in a second modulation format that isdifferent than the first modulation format, and wherein the processor,first antenna, second antenna, radio receiver, radio transmitter,battery, and fault tolerant circuit element are hermetically sealedinside the non-conductive housing, and wherein the processor of thefirst explosion-proof communication relay device is configured withprocessor executable software instructions to perform operations furthercomprising establishing a communication link with the secondexplosion-proof communication relay device.
 16. The communication systemof claim 15, wherein the first explosion-proof communication relaydevice further comprises: a camera coupled to the processor of the firstexplosion-proof communication relay device; and a lens cover arranged toseal and isolate the camera from an exterior atmosphere, and wherein theprocessor of the first explosion-proof communication relay device isconfigured with processor-executable software instructions to performoperations further comprising: receiving instructions from the secondexplosion-proof communication relay device; and adjusting a resolutionof video information collected by the camera based on the receivedinstructions.
 17. The explosion-proof communication device of claim 1,wherein the first frequency modulation format and second frequencymodulation format are different formats, the formats comprisingamplitude modulation, frequency modulation, phase modulation, LTE,CDMA2000, EVDO, WCDMA, HSPA, IS-136, GSM, WiMax, WiFi, AMPS, DECT,TD-SCDMA, and TD-CDMA.